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  • Wissenschaftspark Albert Einstein  (5)
  • Akad. der Künste
  • SB Premnitz
  • Weeks, Wilford F.  (5)
  • 1
    Book
    Book
    Salinity variations in sea ice (1973)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    UID:
    kobvindex_GFZ123014
    Format: iii, 23 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 310
    Content: CONTENTS: Introduction. - Field sites and procedures. - Results. - Discussion. - Conclusions. - Literature cited. - Appendix A: Tabulation of AIDJEX core data. - Appendix B: Tabulation of average salinity/ice thickness data. - Abstract.
    Content: The salinity distribution in multiyear sea ice is dependent on the ice topography and cannot be adequately represented by a single average profile. The cores collected from areas beneath surface hummocks generally showed a systematic increase in salinity with depth from 0 0/00 at tne surface to about 4 0/00 at the base. The cores collected from areas beneath surface depressions were much more saline and displayed large salinity fluctuations. Salinity observations from sea ice of varying thicknesses and ages collected at various arctic and subarctic locations revealed a strong correlation between the average salinity of the ice, S, and the ice thickness, h. For salinity samples collected from cold sea ice at the end of the growth season, this relationship can be represented by two linear equations: S = 14.24 - 19.39h (h? 0.4 m) ; S = 7.88 - 1.59h (h 〉 0.4 m) . It is suggested that the pronounced break in slope at 0.4 m is due to a change in the dominant brine drainage mechanism from brine expulsion to gravity drainage. A linear regression for the data collected during the melt season gives S = 1.58 + 0.18h. An annual cyclic variation of the mean salinity probably exists for multiyear sea ice. The mean salinity should reach a maximum at the end of the growth season and a minimum at the end of the melt season.
    Note: MAB0014.001: ZSP-202-310 , Online frei verfügbar
    In: Research report
    Language: English
    Keywords: Forschungsbericht
    URL: http://www.worldcat.org/oclc/32485561
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  • 2
    Book
    Book
    Mechanical properties of multi-year sea ice : phase II: test results (1985)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    UID:
    kobvindex_GFZ20190703141414
    Format: vi, 89 Seiten , Illustrationen
    Series Statement: CRREL Report 85-16
    Content: This report presents the results of the second phase of a test program designed to obtain a comprehensive understanding of the mechanical properties of multi-year sea ice from the Alaskan Beaufort Sea. In Phase 2, 62 constant-strain-rate uniaxial compression tests were performed on horizontal and vertical ice samples from multi-year pressure ridges to examine the effect of sample orientation on ice strength. Also conducted were 36 constant-strain-rate tension tests, 55 conventional triaxial tests and 35 constant-load compression tests on multi-year pressure ridge samples to provide data for developing ice yield criteria and constitutive laws. Data are presented on the strength, failure strain and modulus of multi-year sea ice under different loading conditions. The effects of ice temperature, porosity, structure, strain rate, confining pressure and sample orientation on the mechanical properties of multi-year sea ice are examined.
    Note: CONTENTS Abstract Preface Introduction Field sampling program Site selection and description Coring procedures Core logging procedures Shipping and storage of ice samples Ice description Salinity and density Structure Constant-strain-rate compression tests Test variables Uniaxial compressive strength Strength and structure Strength and porosity Residual compressive strength Failure strain Initial tangent modulus Constant-strain-rate uniaxial tension tests Test variables Uniaxial tensile strength Failure strains Initial tangent modulus Constant-strain-rate triaxial tests Equipment Test variables Synthane end caps Triaxial strength Failure strains Initial tangent modulus Effect of sinthane end caps on results Constant-load compression tests Test variables Test results Conclusions Literature cited Appendix A: Ice structure profile of ridge C core Appendix H: Test data Appendix C: Static determination of Young's modulus in sea ice
    In: CRREL Report, 85-16
    Language: English
    Keywords: Forschungsbericht
    URL: https://apps.dtic.mil/dtic/tr/fulltext/u2/a166333.pdf
    URL: https://hdl.handle.net/11681/9414
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  • 3
    Book
    Book
    Profile properties of undeformed first-year sea ice (1988)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    UID:
    kobvindex_GFZ20190724152222
    Format: v, 63 Seiten , Illustrationen
    Series Statement: CRREL Report 88-13
    Content: In many sea ice engineering problems the ice sheet has been assumed to be a homogeneous plate whose mechanical properties are estimated from the bulk salinity and average temperature of the ice sheet. Typically no regard has been given to the vertical variation of ice properties in the ice sheet or to the time of ice formation. This paper first reviews some of the mechanical properties of sea ice, including the ice tensile, flexural and shear strengths, as well as the ice modulus. Equations for these properties are given as functions of the ice brine volume, which can be determined from the ice salinity and temperature. Next a numerical, finite difference model is developed to predict the salinity and temperature profiles of a growing ice sheet. In this model ice temperatures are calculated by performing an energy balance of the heat fluxes at the ice surface. The conductive heat flux is used to calculate the rate of ice growth and ice thickness by applying the Stefan ice growth equation. Ice salinities are determined by considering the amount of initial salt entrapment at the ice/water interface and the subsequent brine drainage due to brine expulsion and gravity drainage. Ice salinity and temperature profiles are generated using climatological data for the Central Arctic basin. The predicted salinity and temperature profiles are combined with the mechanical property data to provide mechanical property profiles for first-year sea ice of different thicknesses, grown at different times of the winter. The predicted profiles give composite plate properties that are significantly different from bulk properties obtained by assuming homogeneous plates. In addition the failure strength profiles give maximum strength in the interior of the sheet as contrasted with the usual assumption of maximum strength at the cold, upper ice surface. Surprisingly the mechanical property profiles are only a function of the ice thickness, independent of the time of ice formation.
    Note: CONTENTS Abstract Preface Introduction Structure Composition Mechanical properties Strength Elastic constants The temperature-salinity model Temperature profiles Salinity profiles Composite plate properties Results Conclusions Literature cited Appendix A: Details of the equations for ice surface temperature and conductive heat flux Appendix B: Calculated profile and bulk properties of an ice sheet of varying thickness Appendix C: Calculated profile and bulk properties of 30- and 91-cm-thick ice sheets
    In: CRREL Report, 88-13
    Language: English
    Keywords: Forschungsbericht
    URL: https://apps.dtic.mil/docs/citations/ADA213087
    URL: https://hdl.handle.net/11681/9071
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  • 4
    Book
    Book
    Equations for determining the gas and brine volumes in sea ice samples (1982)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    UID:
    kobvindex_GFZ20190417095858
    Format: 13 Seiten , Illustrationen
    Series Statement: CRREL Report 82-30
    Content: Equations are developed that can be used to determine the amount of gas present in sea ice from measurements of the bulk ice density, salinity and temperature in the temperature range o f-2 to -30°C. Conversely these relationships can be used to give the density of sea ice as a function of its temperature and salinity, considering both the presence of gas and of solid salts in the ice. Equations are also given that allow the calculation of the gas and brine volumes in the ice at temperatures other than that at which the bulk density was determined.
    In: CRREL Report, 82-30
    Language: English
    Keywords: Forschungsbericht
    URL: https://cdm16021.contentdm.oclc.org/digital/collection/p266001coll1/id/7048
    URL: https://hdl.handle.net/11681/9372
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  • 5
    Book
    Book
    Mechanical properties of multi-year sea ice : Phase I: Test results (1984)
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
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    UID:
    kobvindex_GFZ20190425155353
    Format: v, 107 Seiten , Illustrationen
    Series Statement: CRREL Report 84-9
    Content: This report presents the results of the first phase of a test program designed to obtain a comprehensive understanding of the mechanical properties of multi-year sea ice from the Alaskan Beaufort Sea. In Phase I, 222 constant-strain-rate uni-axial compression tests were performed on ice samples from ten multi-year pressure ridges to examine the magnitude and variation of ice strength within and between pressure ridges. A limited number of constant-strain-rate compression and tension tests, constant-load compression tests, and conventional triaxial tests were also performed on ice samples from a multi-year floe to provide preliminary data for developing ice yield criteria and constitutive laws for multi-year sea ice. Data are presented on the strength, failure strain, and modulus of multi-year sea ice under different loading conditions. The statistical variation of ice strength within and between pressure ridges is examined, as well as the effects of ice temperature, porosity, structure, strain rate and confining pressure on the mechanical properties of multi-year sea ice.
    Note: CONTENTS Abstract Preface Introduction Field Sampling Site selection and description Ice sampling procedures Shipping and storage of ice samples Testing Techniques Multi-year Pressure Ridge Tests Ice description Sampling scheme and test variables Uniaxial compressive strength Residual compressive strength Failure strains Initial tangent modulus Statistical Variations in Ice Strength Differences in strength above and below level ice Sources of the variation in strength Shape of the strength histograms Multi-year Floe Ice Tests Ice description Uniaxial compressive strength Constant-load compression tests Constant-strain-rate tension tests Triaxial tests Conclusions Literature Cited Appendix A: Structural profile of a multi-year pressure ridge core Appendix B: Ridge uniaxial compression test data Appendix C: Structural profile of the continuous multi-year floe core Appendix D: Multi-year floe test data
    In: CRREL Report, 84-9
    Language: English
    Keywords: Forschungsbericht
    URL: https://apps.dtic.mil/docs/citations/ADA144132
    URL: https://hdl.handle.net/11681/9279
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